Pulmonary-renal syndrome is defined as the combination of diffuse alveolar haemorrhage (DAH) and glomerulonephritis. The majority of cases are initiated by small vessel vasculitides presenting antineutrophil cytoplasmic autoantibodies (ANCA): Wegener's granulomatosis (WG), microscopic polyangiitis (MPA) and Churg-Strauss-syndrome (CSS). Up to 25% of these ANCA-associated vasculitides (AAV) have also an increased venous thromboembolic risk due to circulating anti-plasminogen antibodies. Pulmonary-renal syndrome in AAV is often fatal without treatment, which still relies on immunosuppression by cytotoxic agents. As such therapy may be lethal itself, accurate assessment of disease severity is mandatory. In this scenario, plasma exchange (PLEX) has proven a fast-acting therapeutic adjunct during severe disease as it limits the use of immunosuppressives and their life-threatening side effects. Novel biomarkers of AAV activity, as well as data from randomized trials investigating new agents, will be essential to improve treatment of severe and refractory forms in the future.
